The present invention is related to a liquid crystal display technique, and more specifically, to an active-matrix-type color liquid crystal display technique using switching elements such as thin-film transistors (will be abbreviated as xe2x80x9cTFTxe2x80x9d hereinafter) and color filters in pixel units.
Recently, as a flat panel display, a color liquid crystal display apparatus has been attracted. In particular, since an active-matrix-type color liquid crystal display apparatus (TFT-LCD) has the superior image qualities, it is widely used as a display for a personal computer.
Normally, in such a color liquid crystal display apparatus, a TFT substrate in which TFT elements are formed on a one-side inner surface of a pair of substrates, and a color filter substrate in which color filter patterns are formed on the other inner surface are overlapped with each other, and then liquid crystal is filled between the substrates to constitute a liquid crystal display apparatus.
Currently, in such a liquid crystal display apparatus, it is required to improve the image quality, so that higher precision thereof is required. In general, when the pixel size is decreased, high precision can be realized in a substrate having the same screen size. However, since the wiring width and the dimension of a thin-film transistor cannot be reduced in proportional to the pixel size, the aperture ratio within a single pixel is lowered.
Furthermore, in view of the recent productivity, such a method of manufacturing a liquid crystal display apparatus is employed in which a large-sized glass substrate is used, the substrates are overlapped with each other in a batch mode, and multi-plane cutting is carried out. In this method, since the TFT substrate and the color filter substrate are overlapped with each other, overlap margin would be reduced when the substrate size is increased and the pixels on the TFT side and the pixels on the color filter side are decreased. As a result, the aperture ratio and the productivity would be lowered.
To avoid this difficulty, as JP-A-10-39292 for example, it is proposed such a structure that the filter is formed on the substrate provided with the color TFT elements. In the description of the patent application, the protection film is formed on the switching element, the signal lines and the scanning lines in order to prevent ions or elements (e.g., copper ions and zinc ions), which are contained in pigment, dye, ink, or the like employed to form the color filter, from entering into the switching element portions formed on the array substrate. Thereby, it is possible to prevent the malfunction and the erroneous operations of the switching elements. The protection film is formed using the organic material or the inorganic material.
However, in the above-described so-called xe2x80x9cactive-matrix-type liquid crystal display elementxe2x80x9d, there are the following problems. That is, in case that the above-described protection film is formed using organic material such as an epoxy resin or an acrylic resin, an alkali water solution developing fluid is generally employed while the color filter is formed. The protection film made of the organic material cannot shield water components. Depending upon sorts of wiring layers, the wiring layers are corroded by alkali components and water components, and the switching elements are damaged and/or operated under error state by the invaded alkali components.
On the other hand, in case that the protection film is formed by inorganic material, the flatness thereof is deteriorated, so that the difference in level of the element structures thereunder cannot be eliminated. As a result, the thickness of the color filter pattern formed thereon is fluctuated, which may deteriorate the spectral characteristic of the color filter.
A problem to be solved by the present invention is to realize a technique by which the spectral characteristic of the color filter is not deteriorated even when the protection film is formed by inorganic material.
An object of the present invention is to solve the above-explained problem, to improve the conventional technique, and to provide a color liquid crystal display technique in high precision and in high image quality by increasing the aperture ratio of a pixel to improve brightness.
In order to achieve the above-explained object, in the present invention:
(1) A color liquid crystal panel is constructed by forming on one substrate of a pair of substrates which sandwich liquid crystal, switching elements arranged in a matrix shape in correspondence with pixels; a wiring portion of the switching elements; a pixel electrode connected to the wiring portion; and a color filter layer formed between the pixel electrode and an inorganic insulating layer for covering the wiring portion of the switching elements, including a lower light-transmission flatted layer and a primary-color-type colored pattern, and provided with an opening through which a connection portion of the wiring portion of the switching elements and the pixel electrode is penetrated, and by forming a common electrode commonly used for plural pixels on the other substrate.
(2) A color liquid crystal panel is constructed by forming on one substrate of a pair of substrates which sandwich liquid crystal, switching elements arranged in a matrix shape in correspondence with pixels and made of thin-film transistor elements; a wiring portion of the switching elements; a pixel electrode connected to the wiring portion; and a color filter layer formed between the pixel electrode and an inorganic insulating layer for covering the wiring portion of the switching elements, including a lower light-transmission flatted layer, a primary-color-type colored pattern and an upper light-transmission protection layer, and provided with an opening through which a connection portion of the wiring portion of the switching elements and the pixel electrode is penetrated, and by forming a common electrode commonly used for plural pixels on the other substrate.
(3) A color liquid crystal display apparatus is arranged by forming on one substrate of a pair of substrates which sandwich liquid crystal, switching elements arranged in a matrix shape in correspondence with pixels; a wiring portion of the switching elements; a pixel electrode connected to the wiring portion; and a color filter layer formed between the pixel electrode and an inorganic insulating layer for covering the wiring portion of the switching elements, including a lower light-transmission flatted layer and a primary-color-type colored pattern, and provided with an opening through which a connection portion of the wiring portion of the switching elements and the pixel electrode is penetrated, and by forming a common electrode commonly used for plural pixels on the other substrate, wherein the pixel electrode is driven by the switching elements in response to an image signal; and the liquid crystal is driven by a voltage applied between the pixel electrode and the common electrode to form an image.
(4) A color liquid crystal display apparatus is arranged by forming on one substrate of a pair of substrates which sandwich liquid crystal, switching elements arranged in a matrix shape in correspondence with pixels and made of thin-film transistor elements; a wiring portion of the switching elements; a pixel electrode connected to the wiring portion; and a color filter layer formed between the pixel electrode and an inorganic insulating layer for covering the wiring portion of the switching elements, including a lower light-transmission flatted layer, a primary-color-type colored pattern and an upper light-transmission protection layer, and provided with an opening through which a connection portion of the wiring portion of the switching elements and the pixel electrode is penetrated; and by forming a common electrode commonly used for plural pixels on the other substrate, wherein the pixel electrode is driven by the switching elements in response to an image signal; and the liquid crystal is driven by a voltage applied between the pixel electrode and the common electrode to form an image.
(5) In the above-described (3) or (4), the color filter layer is constructed so that the lower light-transmission flatted layer, the primary-color-type colored pattern and the upper light-transmission protection layer are made of photosensitive resin.
(6) In the above-described (3) or (4), the color filter layer is constructed so that the lower light-transmission flatted layer and the upper light-transmission protection layer are made of thermosetting resin.
(7) In the above-described (3), (4) or (5), the color filter layer is constructed so that the lower light-transmission flatted layer is a polyimide film in which a polyimide precursor whose molecular terminal is end-capped is imidized by heat-curing.
(8) In any one of the above-described (3) to (7), an external electrode terminal provided every wiring is covered with the inorganic insulating layer, is covered with at least one of the lower light-transmission flatted layer and the upper light-transmission protection layer, and is provided on a substrate which has an opening for exposing the external electrode terminal portion.
(9) A color liquid crystal display apparatus is arranged by forming on one substrate of a pair of substrates which sandwich liquid crystal, switching elements arranged in a matrix shape in correspondence with pixels; a pixel electrode connected to a wiring portion of the switching elements; a common electrode arranged substantially parallel to a longitudinal direction of the pixel electrode and substantially along a plane direction, and commonly used to plural pixels; a color filter layer formed among the common electrode, the pixel electrode and an inorganic insulating layer for covering the wiring portion of the switching elements, and including a lower light-transmission flatted layer and a primary-color-type colored pattern, wherein the pixel electrode is driven by the switching elements in response to an image signal; and the liquid crystal is driven by a voltage applied between the pixel electrode and the common electrode to form an image.